In commercial practice in the plastic art, particularly the thermosetting resin art, there exists continuous efforts to reduce the cure times of resins consistent with obtaining products of acceptable performance and appearance. The reduction of cure times improves and often makes attractive the economics of plastic molding processes, adhesives and coatings. Further, reduced cure times can lower unit costs and improve productivity.
Efforts to increase curing speed are particularly prevalent in the epoxy resin art and many materials and combinations of materials have been taught by the art for achieving rapid cure of epoxy resins. However, there often is encountered in the prior art fast cure of epoxy resins, an adverse effect on one or more physical properties (e.g. clarity, color, impact resistance and hardness to name a few) of the cured resin as compared to a slow cured resin system. Such adverse effects (e.g. reduction in clarity, darker color and lower impact resistance) often limits the usefulness or excludes the use of fast curing epoxy resin systems in many applications and thereby restricts, if not precludes the use of many prior art materials or combinations of materials for curing epoxy resins. Thus, in the epoxy resin art it is desired to employ materials or combinations of materials which provide rapid cure of the epoxy resin while having little or no effect on the physical properties of the cured epoxy resin.